List of top Chemistry Questions asked in JEE Main

\(N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)\)
Consider the above reaction, the limiting reagent of the reaction and number of moles of NH₃ formed, respectively are :

100 mL of 5% (w/v) solution of NaCl in water was prepared in 250 mL beaker. Albumin from the egg was poured into NaCl solution and stirred well. This resulted in a/an :

The first ionization enthalpy of Na, Mg and Si, respectively, are : 496, 737 and 786 kJ mol^–1. The first ionization enthalpy (kJ mol^–1) of Al is:

In metallurgy the term “gangue” is used for :

Resistance of a conductivity cell (cell constant 129 m^–1) filled with 74.5 ppm solution of KCI is 100 Ω (labelled as solution 1). When the same cell is filled with KCl solution of 149 ppm, the resistance is 50 Ω (labelled as solution 2). The ratio of molar conductivity of solution 1 and solution 2 is \(\frac{\Lambda_1}{\Lambda_2} = x \times 10^{-3}\). The value of x is _________. (Nearest integer)
(Given : molar mass of KCl is 74.5 g mol^–1).

Ionic radii of cation A⁺ and anion B^– are 102 and 181 pm, respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for B^–. A⁺ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is _____pm. (Nearest integer)

1.80 g of solute A was dissolved in 62.5 cm³ of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is ____ g mol^–1.
[Given : Freezing point of ethanol is 156.0 K, Density of ethanol is 0.80 g cm^–3, Freezing point depression constant of ethanol is 2.00 K kg mol^–1]

For a cell, \(Cu(s)|Cu^{2+}(0.001M)||Ag^+(0.01M)|Ag(s)\)
the cell potential is found to be \(0.43 V\) at \(298 K\). The magnitude of standard electrode potential for \(Cu^{2+}/{Cu}\) is ____ \(× 10^{–2}\) V.
[Given: \(E_{Ag^+/Ag^⊖}=0.80\) V and \(\frac {2.303RT}{F}=0.06 V\)]

Sum of oxidation state (magnitude) and coordination number of cobalt in \(Na[Co(bpy)Cl_4]\) is____ .
(Given : bpy =)

Consider the following sulphur based oxoacids.
\(H_2SO_3,H_2SO_4,H_2S_2O_8 \)and \(H_2S_2O_7\)
Amongst these oxoacids, the number of those with peroxo (O–O) bonds is_____.

The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives:

Lithium nitrate and sodium nitrate, when heated separately, respectively, give :

A 1.84 mg sample of polyhydric alcoholic compound ‘X’ of molar mass 92.0 g/mol gave 1.344 mL of H₂ gas at STP. The number of alcoholic hydrogens present in compound ‘X’ is____.

Number of lone pairs of electrons in the central atom of SCl₂, O₃, CIF₃ and SF₆, respectively, are:

In following pairs, the one in which both transition metal ions are colourless is :

In neutral or faintly alkaline medium, KMnO₄ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be

Which among the following pairs has only herbicides?

Which among the following is the strongest Bronsted base?

Which among the following pairs of the structures will give different products onozonolysis? (Consider the double bonds in the structures are rigid and not delocalized)

The number of stereoisomers formed in a reaction of (±) Ph (C = O) C (OH) (CN) Ph with HCN is_____.
[Where, Ph is – C₆H₅]

The number of chlorine atoms in bithionol is ______ .

Octahedral complexes of copper(II) undergo structural distortion (Jahn-Teller). Which one of the given copper(II) complexes will show the maximum structural distortion?
(en – ethylenediamine;H₂N−CH₂−CH₂−NH₂)

Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and retard photosyn-thesis is